1. Field of the Invention
The present invention is directed to a method and apparatus for creating depth images that have changing display information and, more particularly to depth images in which display information, distinct from the normal depth/look around display information, appears and disappears as the perspective of the viewer changes.
2. Description of the Related Art
Conventional depth images provide the viewer with a sense of depth which is some times called binocular stereopsis. Conventional depth image displays, either of the lenticular or barrier type, because a stereo effect is being provided, present sightly different scene information to the viewer as the viewer's head moves in a horizontal direction in front of the depth image. This effect called a look around effect occurs because each eye is presented with a different image or view of the scene and as the position of the eye moves relative to the depth image the view presented to each eye changes. This is shown in the lenticular photograph type depth image 8 illustrated in FIG. 1. In this figure when the eyes 10 and 12 of a viewer are in position 14 the viewer sees the image slices from scenes A and C respectively as illustrated by the solid lines. The A scene is a view slice of the scene from a viewpoint to the left of the viewpoint of scene C. When the viewer's eyes 10 and 12 move to position 16 the image slices seen by each eye change. As depicted by the dashed lines the left eye sees image slices from scene B and the right eye sees slices from scene D. When the viewpoint of the scene A is to the left of the viewpoint of scene B, B is to the left of C and C is to the left of D, as the viewers' head moves, the viewer will see progressively different viewpoints of the scene. Because the mind of the viewer fuses the slices of the same scene reaching each eye the viewer senses depth in the photograph being viewed. If the different viewpoints of the scene gradually expose a hidden object, the viewer experiences the ability to look around objects in the depth photograph. This experience of depth is provided even though the lenticular photograph 8 is a generally planar object. The ability of the lenticular photograph to provide different image slices to the eye is possible because an image substrate 20 includes adjacently recorded image slices 22, 24, 26, etc. each of which is projected in a different direction by the cylindrically shaped lenses, called lenticules 28, which are part of the lenticular faceplate 29 positioned in front of the substrate 20. In barrier type depth images a barrier strip faceplate is substituted for the lenticular faceplate. Additional information on the background and the theory of depth images can be obtained from Okoshi, Three-Dimensional Imaging Techniques, 1976 published by Academic Press. Conventional depth images, such as those discussed above, present the viewer with images from the same scene with changes in image information being limited to changes in content being provided by different viewpoints of the same scene.
Lenticular viewing devices currently exist in which the information presented changes as the viewpoint of the lenticular object changes. These objects, typified by lenticular baseball cards and prizes found in boxes of caramel coated nuts and popcorn, present the viewer with different pictures of different scenes as the vertical viewpoint changes. For example, from one viewpoint the viewer would see a picture of a baseball player and from a different vertical viewpoint the viewer would see a picture of a different baseball player. These pictures are planar pictures with no sense of depth being provided.
What is needed is a depth image that radically changes the information provided to the viewer as the viewpoint changes horizontally while the sense of realism or depth is preserved.